Feeding mechanism for rock drills



J. C. CURTIS FEEDING MECHANISM FOR ROCK DRILLs Jan. 23, 1936.

Filed Feb. 2, 1955 2 Sheets-Sheet l m W Y C. R M @ME C m N m n wm H w A V.. B

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Jan. 28, 1936. 1 Q CUR-|15 FEEDING MECHANISM FOR ROCK DRILLS 2 Sheets-Sheet 2 Filed Feb. 2, 1953 wml www@

JOHN C. CUI? 775 INVENTOR ATTORNEY Patented Jan. 28, 1936 UNITED STATES PATENT OFFICE FEEDING MECHANISM FOR ROCK DRILLS Application February 2, 1933, Serial No. 654,802

6 Claims.

This invention relates broadly to rock drills, but more particularly to feeding mechanism for rock drills of the drifter type.

One of the objects of this invention is to provide 5l a rock drill with an improved feeding mechanism of simple design and economic of manufacture.

Another object of this invention is to provide a rock drill with a feeding mechanism transmitting forward and rearward motion to the drill at a uniform rate of power, but at a greater rate of speed than that of the feeding element.

Other objects and advantages more or less ancillary to the foregoing and the manner in which the various objects are attained, reside in the specic construction and aggroupment of the elements peculiar to this structure, as will become apparent froml a more complete examination of this specification, in the claims of which there are assembled certain specific combinations of parts and specific constructions indicative of the scope and spirit of the invention.

In the drawings which illustrate a preferred embodiment of the invention.

Fig. l is a longitudinal view, partly in section, of the machine assembly.

Fig. 2 is an enlarged cross sectional view taken in a plane indicated by line 2 2 in Fig. 1.

Fig. 3 is an enlarged cross sectional View taken in a plane indicated by line 3 3 in Fig. 2.

Fig. 4-is an enlarged view of a portion of the front end of the feed tube illustrating the manner in which the tension of the chain may be adjusted.

Fig. 5 is an enlarged sectional view of the feed tube partition shown in Fig. 1.

Fig. 6A is an enlarged View illustrating how the ends of the chain are fastened to the feed tube.

Fig. 'l is an enlarged View of the backhead secured to one end of the feed tube.

Figs. 8 and 9 are cross sectional views taken in a plane indicated by line 8--8 in Fig. 7, illustrating the throttle valve in different positions.

Referring to the drawings in which like symbols designate corresponding parts throughout the several views, I represents a rock drill or drilling motor capable to deliver blows to a drill steel I I. The rock drill has its lower Wall formed with a pair of longitudinally disposed ribs I2, capable of slidable engagement with 4the guides I3, which are disposed on the upper wall of a rock drill support I4. This support is formed of a rectangular tubular member constituting a feed tube I5, having attached to its lower external Wall .a cone I', by which the support may be secured 55 to any appropriate frame. Disposed within the feed tube I5,- there is a member or partition I6 secured therein by bolts II. This partition is located tov divide the tube I5 in two substantially equal portions I8 and I9. The partition I6 is formed with a centrally disposed bore having secured therein a member 20 formed with an enlarged head 2| which extends into the feed tube portion I8. The member 2D is internally threaded to receive a member 22 which is also formed with an enlarged head 23 extending into the feed tube portion I9. Clamped between the heads 2l and 23, on each side of the partition I6, there is a packing 24 and 25, capable of iluid tight engagement with the internal Wall of the feed tube I5. Formed within the heads 2l and 23 of the members 29 and 22, there is an enlarged cavity or bore 26 and 2l, the purpose of which will be explained hereafter. Leading from the bore 26 into the bore 21, there is an aperture Within which there is reciprocably mounted a rod 28. Circumventing this rod and capable of fluid tight engagement therewith, there are V-shaped packings 29 and 3e, which are disposed in opposite direction into grooves formed within the members 20 and 22.

The end portions 3| and 32 of the rod 28 are restricted in diameter to form shoulders 33. Mounted on the restricted portion 3l, there is a piston 34 comprising a packing 35 in fluid tight engagement with the internal Wall of the feed tube I5, and a retainer 36 having its longitudinal movement limited by its engagement against the shoulder 33. Clamped against the piston 34, there is a bracket 31 which is secured thereon by a nut 38, in screw tight engagement with the end of the restricted portion 3l. Mounted in the restricted portion 32, there is a piston 39, comprising a packing 40 and retainer 4I. A bracket 42 is also clamped against the piston 39 by a nut 43. The retainers 36 and 4I are properly machined for close fit engagement into the bores 26 and 2l of the members 2I and 23. The brackets 37 and 42 are conveniently machined to receive the sprockets 44 and 45, rotatably mounted on a transversally disposed shaft 46.

The right end of the tube I5, hereafter designated as the front end of the tube, is closed by a front head 4l secured therein by means of bolts or the like. Disposed on the lower wall of the feed tube I5, adjacent the front head 4l, there is secured a member 41 formed with a plurality of equally spaced bores 48, located on a plane coinciding with the vertical plane passing through the middle of the sprocket 44. Pressed Within these bores, there are pins 49 having a restricted portion protruding therefrom and capable to rebores 48.

The upper front end portion of the feed tube I5 is properly machined to receive on each side thereof a bracket 54 having a slot 55 through which bolts 56 are disposed for securing the brackets to the tube. Rotatably mounted between these brackets, there is a sprocket 51 whichi" protrudes to the exterior of the tube I5 through a slot 58.

The rear end of the feed'tube I5 is closed by Y a backhead 59 secured thereto by means of bolts or the like. of the feed tube I5, adjacent the backheadg, there is secured a member .59' formed in a manner Vsimilar to the member 41', for the purpose of securing the other end of the chain 5|. The upper rear end portion of the feed tube I5 is conveniently machined to receive a sprocket 66, rotatably mounted on a transversally disposed shaft 6I. This last sprocket protrudes to the exterior of the feed tube I5 through a slot 62.

Rotatably mounted within the backhead 59, there is a throttle `valve 63, which may be actuated by means of a handle 64. Centrally disposed within this throttle valve, there is an enlarged bore 65, into which pressure fluid may be admitted from its source of supply. Leading` from the bore 65, there are two radially disposed passages 66 and 61. Formed on Vthe external wall of the throttle valve-between the passages 66 and 61, there is a groove 69 in constant communication with the vent hole 69. The passage 66 is capable of communication with the portion I8 of the feed tube I5, through a restricted conduit 1I, which opens into the feed tube adjacent the partition I6. `The passage 51 may similarly be in communication with the portion I9 of the feed tube I5, through a restricted conduit 18, opening therein adjacent the partition I6.

The chain 5I, having one of its endsnattached to the front head 41, and the other to the backhead 59, is of sucient length to pass under the sprocket 44, then` over the adjustable sprocket 51, stationary sprocket 69, and back under the Vreciprocable sprocket 45. At a point substantially equally distant from the ends of the chain, the latter is attached to the rock drill by means of a plug 12. This plug is secured to the rock drill into Yan apertured lug 13 which Vextends downwardly from the lower wall thereof. The plug 12 is formed with a head 14 capable of engagement with the one side of the wall of the lug, and has its other end provided with an eccentrically located restricted portion 15, threaded to receive a nut 16. The upper portion of the plug 12 is formed with teeth 11 capable of engagement with the chain 5I. To permit Ythe free passage of the chain under the rock drill, the latter is formed with a longitudinally disposed groove 18.

In the operation of the mechanism, assuming the throttle valve 63 to be positioned as illustrated in Fig. 9. Pressure uid is admitted from the throttle valve bore 65 into the feed tube portion I8, through the valve passage 66 and conduit 1I. Pressure fluid admitted into that portionof the feed tube will act on the piston 39 to move the latter rearwardly. Simultaneously the feed tube portion I9 is vented to the atmosphere Disposed on the lower internal wall through the conduit 18, valve groove 68, and vent hole 69, thus permitting the rearward movement of the piston 34 and consequently the rearward movement ofthe piston 39, since these pistons are united by the rod 28. During the rearward movement of the pistons, the chain 5I passing under the sprocket 44', will cause the forward movement of the rock drill I Il. Due to the association of the chain 5I with the sprocket 44, which moves rearwardly with the piston, the chain 5I will pull the rock drill forwardly at a double rate of'speed than that of the piston 34. The speed ofthe piston and consequently the speed of feed transmitted by the chain 5I to the rock drill I0, may be regulated by a more or less complete registration ofthe passage 66 with the conduit 16, thus varying theamount of pressure uid admitted into the feed tube. v

Toward the end of the rearward stroke of the pistons 34 and 39, the retainer 36 will enter the bore21 'ofthe member 23, thus compressing the atmosphere therein to create an air cushion for checking the impact of the piston 34 against the partition I6. 1

When it is desired to retract the drilling motor from theV work, the throttle valve 63 may be positioned as illustrated in Fig. 8. In this instance pressurefluid is admitted into the portion I9 of the feed tube I5, through the throttle valve passage 61 and conduit 18. The pressure fluid in that portion of the feed tube will act on the piston 34 to move the latter, together with the piston 29, forwardly. Simultaneously the feed tube portion I8 is vented to the atmosphere through the conduit 1I, throttle valve groove 68 and vent hole 69.

From the foregoing, it will be seen that since the areas of the pistons subjected to the pressure fluid are equal, the speed of the forward movement of the rock drill is equal to the speed of its rearward movement. Consequently, even though the rate of feeding speed transmitted to the drill is greater than that of the feed pistons, the feeding power transmitted to the drill remains constant irrespective of the sense of travel of the latter. Y j

Pressure fluid admitted into the feed tube I5 will act on the packings 35 and 25 or 40 and 24, to assure a fluid tight joint of the different membersrtherein with the internal vwall of the feed tube I5. Similarly any pressure fluid tending to escape around the rod 2 8 from one sideof the partition I6 to another, will be arrested by the action ofthe packings 29 or 30. Y

The tension of the chain 5I may be adjusted, by simply loosening the bolts 56 and sliding the bracket 54, which carry the sprocket 51, into any desired position. Y,

Although the foregoing description is necessarily Vof a detailed character, in order to comstood that the specicrvterminology is not intended to be restrictive or confining and it is to be further understood that variousV rearrangements of parts and modification of structural detail may be resorted to'without departing fromV `60 pletely set forth the invention, it is to be Vunder- Y said tube, a stationary partition between said heads having a rod slidable therethrough uniting said heads, passages for admitting motive fluid into said tube adjacent said partition for actuating said member, a flexible draft element connecting said member to said motor, said element being fastened to said tube and said motor While engaging said member for movement relative thereto during the normal reciprocation of the latter, and openings through said tube through which said element is free to pass from the interior to the exterior of said tube, the position of said openings being such that the motive fluid admitted into said tube is prevented to escape through said openings due to the fluid tight engagement of the heads of said member with the inner wall of said tube irrespective of the position of the former within the latter.

2. In a rock drilling apparatus, a support having a drilling motor slidably guided thereon, a feeding mechanism for said motor comprising a tube having a power actuated member movable back and forth therein, a duality of heads for said members in fluid tight engagement with the inner wall of said tube, a partition between said heads having a rod slidable therethrough uniting said heads, means for admitting pressure fiuid into said tube adjacent said partition for actuating said member, a flexible ,draft element connecting said member to said motor, rotatable bodies carried by said member and tube, said iiexible element while located within said tube extending from one end thereof where it is fastened toward said member for passing around one of said bodies carried thereby and back toward the end of said tube for passing around another of said bodies carried by the latter from where it extends externally of said tube to the motor where it is fastened, and at least one opening through said tube through which said flexible element is free to pass from the interior tc the exterior thereof, the rotatable body carried by said tube being located relatively to said opening in a manner affording said flexible element to remain in spaced relation with the wall of said tube.

3. In a rock drilling apparatus, a support having a drilling motor slidably guided thereon, feeding means for said motor comprising a tube having a power actuated member slidable therein in both directions, a duality of heads for said members in fluid tight engagement with the inner wall of said tube, a partition between said heads having a rod slidable therethrough uniting said heads, means for admitting pressure fluid into said tube adjacent said partition for actuating said member, a mechanism for transmitting the movement of said member in one direction to said motor including a exible element fastened to said motor and to one end of said tube, a duality of rotatable bodies one carried by said tube and the other carried by said member, said flexible element leading from said motor rearwardly over said rst mentioned body, then forwardly over the body carried by said member and thereafter rearwardly to said one end of the tube, said rotatable bodies being located to maintain the portion of said flexible element extending therebetween substantially parallel with the portions extending therefrom to said motor and to said one end of the tube, two of said portions being located within said tube while the other is located externally thereof, an opening through which said element is free to pass from the interior to the exterior of the tube, and means for transmitting the movement of said member in the other direction to said motor, said last means being a replica of said mechanism.

4. In a drilling apparatus, a support having a drilling motor slidably guided relatively thereto, feeding means for said motor including a feed tube formed with two piston chambers having a partition therebetween, a piston within each of said chambers reciprocable therein, a rod through said partition uniting said pistons, means for admitting pressure fiuid into said chambers adjacent said partition for actuating said pistons, a mechanism associated with said pistons and motor for transforming the movement of the former to the latter at a multiplied rate of speed, said mechanism including a system of pulleys of the whip and runner type, and an opening through said tube through which the whip or flexible element incorporated in said system is free to pass from the interior of the tube where it is ailxed to the exterior thereof where it is secured to said motor.

5. In a ,drilling apparatus, a support having a drilling motor slidably relatively thereto, feeding means for said motor comprising a tube having a member slidable therein in both directions, a duality of heads for said member in fluid tight engagement with the inner wall of said tube, a stationary partition between said heads having a rod slidable therethrough uniting said heads, means for admitting pressure fluid between said heads adjacent said partition for actuating said member, a mechanism associated with said member and motor for transmitting the movement of the former to the latter at a greater rate of speed, said mechanism including a system of pulleys of the whip and runner type, one end of the whip or exible element being affixed-to the support and the other to the motor, the runner being carried by said member for movement therewith, and an opening leading from the interior of said tube to the exterior thereof through which the whip is free to pass.

6. In a drilling apparatus, a support having a drilling motor longitudinally slidable relatively thereto, feeding means for said motor comprising a duality of coaxial piston chambers within said support having a partition therebetween, a piston within each of said chambers for longitudinal slidable movement therein in both directions, a rod slidable through said partition uniting said pistons, means for admitting pressure fluid into said chambers adjacent said partition for actuating said pistons, a mechanism for transmitting the movement of said pistons in one direction to said motor, said mechanism incluiing a system of pulleys of the whip and runner type, one end of the Whip or iiexible element incorporated in said system being affixed to said support and the other end to said motor, the runner or longitudinally movable pulley being carried by one of said pistons for movement therewith, an opening throughv said support through which the flexible member is free to pass from the interior to the exterior thereof, and means for transmitting the movement of said pistons in the other direction to said motor, said last means being a replica of said mechanism.

JOHN C. CURTIS. 

